Method and apparatus for film encapsulation of irregularly shaped articles

ABSTRACT

A method and apparatus for shrink-wrapping a heat sealable thermoplastic film about regular and irregular shaped articles is provided, wherein the film is provided above and below the article, one or more heat-sealing blades are generally configured to the article exterior contour to heat seal the film material about the article, the heat-sealing blade having an electrically actuated healing element within insulated material, and the spacing of the heat-sealing blade adjacent the article is intentionally non-uniform in predetermined manner. A contoured heat-sealing blade assembly is provided within split-molds, which may have associated heating ports to control the temperature of the sealing operation within different zones of the mold.

FIELD OF THE INVENTION

The present invention relates to a method and apparatus for heat sealingthermoplastic film about regular and irregular shaped articles, moreparticularly the method and apparatus relate to shrink wrap packingprocesses, which form fit heat sealable plastic films around the profileof regular and irregular shaped articles. This process incorporatesindividually shaped heat-sealing blades, which are machined or likewisemanufactured, to actually match the outer profile of the attended objectto be shrink-wrapped.

PRIOR ART AND RELATED INFORMATION

It is common in the prior art to use heat-sealing pouches, as in U. S.Pat. No. 6,260,705, which simply cover the proposed article and providefor a sealed end. A bottom seal contour bag manufacture is illustratedin U. S. Pat. No. 3,558,406, which is intended to simply provide acontoured end seal. A bag end is contoured to provide an evenlydistributed closure in U. S. Pat. No. 3,053,723.

Shrink-wrap systems are well known in the art. Exemplary thereof areExlfilm Shrink Film of Montreal, Quebec, Canada and Sarasota, Fla.,U.S.A. Automatic heat sealers, heat shrink tunnels and associatedequipment are readily available from companies known in the art, such asClam Seal Corporation, Cleveland, Ohio.

BACKGROUND OF THE INVENTION

The present invention relates to a method and apparatus for heat-sealingthermoplastic film about regular and irregular shaped articles. Moreparticularly the method and apparatus relate to shrink wrap packingprocesses, which form fit heat sealable plastic films around the profileof regular and irregular shaped articles. This process incorporatesindividually shaped heat-sealing blades, which are machined or likewisemanufactured, to actually match the outer profile of the attended objectto be shrink-wrapped.

The apparatus and method of the present invention also contemplates asplit-cavity mold design, which also matches the profile of the attendedobject to be packaged, assists in holding the shrink film in placearound the intended packaged object and defines the location of thesealed film sidewall or margin seals.

SUMMARY OF THE INVENTION

The apparatus and method of the present invention contemplatesshrink-wrapping a heat sealable thermoplastic film about regular andirregular shaped articles through the provision of initially providingthe thermoplastic film above and below the article with margins of thefilm extending beyond the article to be sealed. In accordance withapplicant's invention, one or more heat-sealing blades are generallyconfigured to the article exterior contour to heat-seal the film marginabout the article and provide shrinkage about the article. Specifically,the spacing of the heat-sealing blade adjacent areas of the article, areintentionally non-uniform first positions relative positions of theblade, which are more widely spaced in second positions is contemplated.Heating of the blade and contracting the margins to cause film marginscontacted by the blade first portions to shrink into contact with andabout the article first, and then subsequently film portions contactedby second portions of the blade to shrink into contact and seal aboutthe article second, provide for applicant's novel method and apparatus.

In an exemplary embodiment, an article such as golf club head isprovided with a generally right angle, fairly sharp corner forintersection normally between the shaft and club head. By positioningthe sealing blade first portions more closely to such corner orirregular shaped areas of the exemplary club head and shaft, a moreclean and neat shrink-wrap can be obtained. In a preferred exemplaryembodiment, the spacing of blade first portions is one-third closer thanother portions to cause film movement to occur first into contact withthe irregular shaped article in its irregular position, while secondportions associated with the sealing blade are allowed to move secondlyinto contact with the article in a heat-shrink operation.

In the preferred exemplary embodiment, the article to be enveloped isplaced in a bottom half of a mold, which is designed to facilitatepositioning margins of the film adjacent the article. A top mold isprovided with a hold-down clamp to hold margins of the film in place,while a specifically contoured heat-sealing blade assembly is thenbrought into contact with the film to cause it to shrink in the desiredmanner.

In an alternative split-mold construction, upper and lower mold halvesare provided with a plurality of heat ports with associated valves tocontrol the heating in different areas of the mold, while theshrink-wrap process is completed. Upper and lower portions of the moldmay be provided with heat zones in a further alternative to concentrateheating in particular areas of the article being wrapped, such as in thearea where the irregularity, sharp corner, or objectionableconfiguration is found in the article being wrapped.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a partially exploded view of apparatus employing the method ofshrink wrapping a heat sealable thermoplastic film about regular andirregularly shaped articles in accordance with the present invention.

FIG. 2 is a side-section view illustrating apparatus of FIG. 1 inassembled relationship.

FIG. 3 shows a heat sealable thermoplastic film of general rectilinearconfiguration, which can be positioned above and below the article to besealed.

FIG. 4 is a sleeve of thermoplastic material, sealed at an upper end andopen at lower ends, to fit around an exemplary golf club head.

FIG. 5 illustrates the preferred layout of sealing blade about anexemplary golf head in practicing the method of the apparatus of FIGS. 1and 2.

FIG. 6 illustrates an interim step in the practice of applicant's methodherein.

FIG. 7 illustrates a heat sealable thermoplastic film shrunk evenlyabout an exemplary golf head in accordance with applicant's method.

FIG. 8 shows applicant's heat-sealing blade apparatus of FIG. 1.

FIG. 9 is a section view of the heat-sealing blade apparatus of FIG. 8.

FIG. 10 shows applicant's mold, top and bottom, having heating portspositioned to provide heating zones of the mold cavity.

FIG. 11 is a plan view of the mold of FIG. 10.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to FIG. 1, an exemplary golf club head 10 is illustratedhaving a shaft 11. Typical golf club heads have an intersection,indicated generally at 12, where the shaft and head come together. It isvery desirable to provide a shrinkable thermoplastic film shrink-wrap atsuch location, which tightly adheres to the golf club head and shaftportions without providing an unsightly billet of excess material. Asdisclosed hereinafter, applicant's method of shrink wrapping is intendedto solve such problem.

A mold bottom 20 is provided, having a top surface 21 and internalsupports 22 and 23 for supporting the exemplary golf club head indicatedgenerally at 10. A mold entrance 13 is provided.

As illustrated in FIG. 3, a heat shrinkable thermoplastic film 15 may beprovided in a rectangular configuration to ie above, below andessentially around the golf club head generally indicated at 10 in FIGS.1 and 2. An alternative heat sealable thermoplastic film 16 may also beprovided where an upper end 17 is pre-sealed, while lower openings 18,may be provided for fitting film 16 initially about the exemplary head,indicated generally at 10, in FIG. 2.

As seen in FIGS. 1 and 2, clamp 30, having clamp seat 31, may beinitially fitted down on surface 21 to seal the exemplary heat sealingthermoplastic film 15 about the exemplary club head. Then, in otherwiseknown manner, the upper mold 35 may be brought down around the clamp toprovide an interior chamber 36, as well as a configured heat sealingassembly 27.

In accordance with the apparatus and method of applicant's presentinvention, heat sealing assembly 37 includes a heat sealing blade 38generally configured to the article exterior contour to heat seal 15'smargin about the exemplary golf club head, indicated generally at 10,and shrink film 15 about the exemplary golf club head wherein thespacing of the blade 38 adjacent the club head is intentionallynon-uniform, first portions of blade 28 being closer to the exemplarygolf club head than second portions as will now be explained.

Refering now to FIGS. 8 and 9, it has been found to be particularlydesirable to use a flexible cable heating source 39 to provide thecontoured heating blade configuration contemplated by the presentinvention. Exemplary of such flexible heating cables, is the CableHeater by Watlow, Inc., Columbus, Miss., U.S.A. The range of cablediameter is preferably between 0.068 to 0.0875 diameter. Flexible cable39, according to the present invention, is preferably provided with acover cap that fits over the blade 38. Flexible cable 39 is anelectrically powered resistor, while blade 38 may be an insulatingmaterial.

In a preferred exemplary embodiment, the resistor, cable 39 is made of ametal wire having a high temperature silicon outer coating over asilicon rubber or “Capton”™ polyimide base. Upper blad cover 40 and theblade 38 are preferably made of aluminum and coated with Tefton™.

Hold down guides 41-44, as seen in FIG. 9, are provided to hold thecover 40 over the cable 39 to the blade 38. Guides 41-44 may be made oflongitudinally extending springs to provide a mechanical interferencethat hold the cover 40 to blade 38. Alternative fastener means may beemployed by worker, as in the art.

In accordance with the apparatus and method of the present invention,and referring now to FIGS. 5-7, sealing blade 38 is generally configuredto the exemplary article, the golf club indicated generally at 10 in thepresent example, configured to its exterior in a predeterminedparticular manner. Noting that the exemplary article is of anirregularly non-uniform configuration it is very desirable that theconforming blade 38 be positioned indicated generally at 4 adjacent thesharp edge of the shaft-club arrangement than it is in other areas asindicated generally at 42 and 43.

In a preferred example, blade 38 is positioned adjacent the corner ofthe exemplary golf club and shaft about one-third of the spacing ofblade 38 from second positions as exemplified by the second areasindicated generally at 42 and 43. As heat is applied through blade 38,the thermoplastic film 15 moves inward into engagement at area 141 inthe sharp edge or corner of the illustrative golf club indicatedgenerally at 10 and associated shaft 11. Blade 38 is thus heated andplaced into contact with margins of film 15 contacted by the first bladportions indicated generally at 41, to shirnk quickly into contact withand about the exemplary article first. Other film portions, as indicatedat 43 contacted by the more widely spaced blade 38 configuration, causessuch second portions to shrink into contact and seal about the exemplaryarticle second.

On completion of the sealing action, as seen in FIG. 7, a neat seal iseffected around the exemplary golf club head or article having anirregularly-shaped intersection, or the like, to provide sealing withoutexcess film webbing in the sharp or corner areas, as indicated at 41.The second portions, indicated generally at 43 by way of example, simplycatch up as the thermoplastic film shrinks around the exemplary articleto a complete and enveloping condition, but the careful pre-positioningof the flexible blade 38 to be closer in areas where a sharp corner orobjectionable irregularity occurs and results in the complete envelopingof the article by the thermoplastic film without there being unwantedexcess material, as might be occasioned by heat shrinking ofthermoplastic film about such article by other methods using otherapparatus.

An exemplary split-mold design is illustrated in FIGS. 10 and 11, inaccordance with the method and apparatus of the present invention.Split-mold 50 is provided with a top 51 and bottom 52. A plurality ofheating ports 53, 54 are provided in the top and bottom portions of themold, as are associated control valves 55 and 56. A source of hot air 57and 58 are each connected to associated plenums 59 and 60, which lead tothe plurality of heating ports.

As seen in plan view of FIG. 11, the individual heating ports 53 and 54of FIG. 10 may be positioned in two zones to provide heat in desirableareas. As seen in FIG. 11, first zones can be provided through groupingof hot air ports, indicated generally at 61 and 62, which are groupedalong the side of the exemplary article, golf club 10 in the presentexample, away from the sharp corner or intersection area to facilitateoverall control of sealing of the film about the article. Importantsecond zones indicated, generally at 63 and 64, may be provided in theareas of the sharp or irregularly shaped intersection of the article,golf club head indicated generally at 10 and shaft 11 in the presentexample, to encourage fluid movement in this area, which in accordancewith the present invention is one of the pre-selected areas for movingthe material more quickly into contact with the article, to provide asmooth shrink wrap arrangement.

The heating ports 53, 54, as well as the exemplary heating zonesindicated generally at 61-64, may be provided at different heatingtemperatures, or at the same temperature at different times, tofacilitate the shrink-wrap procedure of the present invention.

Having thus described a preferred exemplary embodiment of the apparatusand method of the present invention, it should be understood by thoseskilled in the art that various modifications, adaptations andalternative embodiments thereof, may be made within the scope and spiritof the present invention which is defined by the following claims.

1. A method of shrink wrapping a heat shrinkable thermoplastic filmabout regular and irregular shaped articles comprising: providing saidfilm above and below said article with margins of said film extendingbeyond said article; providing one or more heat sealing blade generallyconfigured to the article exterior contour to heat seal said film marginabout said article and shrinkage of said film about said article whereinthe spacing of said blade adjacent said article is intentionallynon-uniform, first portions of said blade being closer to said articlethan second portions; and heating said blade and contacting said marginsto cause film margins contacted by said blade first portions to shrinkinto contact with and about said article first and film portionscontacted by said second portion to shrink into contact and seal aboutsaid article second.
 2. The method of claim 1 wherein said article hasone or more inwardly shaped corner to be wrapped; and said blade firstportions are spaced from said one or more corners a distance of aboutone-third the spacing of said blade second portions for said article. 3.The method of claim 1 wherein: said film is provided as one piece foldedover and under said article.
 4. The method of claim 1 wherein: said filmis provided as a film pouch fitted about said article.
 5. The method ofclaim 1 comprising: clamping said film about said article before sealingof said margins.
 6. The method of claim 1 comprising: positioning saidarticle in a bottom part of a split mold; mounting said heat seatingblade on an upper part of said mold.
 7. The method of claim 6comprising: heating interior zones of said mold through heat introducingports positioned to allow heating of some interior zones of said mold totemperatures which differ from that of other interior zones of saidmold.
 8. The method of claim 1 comprising: heating said heat one or moresealing blade by an electrically activated flexible cable heaterprovided within said one or more blade. 9-19. (canceled)
 20. A method ofshrink wrapping a heat sealable and shrinkable thermoplastic film aboutan article to be wrapped, said method comprising: staging a sequence ofshrinkage of different parts of said film about said article to cause afirst tight fit of said film about preselected parts of said article anda second subsequent tight fit of said film about other parts of saidarticle.
 21. The method of claim 20 wherein said staging comprises:providing a heat sealing blade for sealing and heating of said film tocause shrinkage about said article; and spacing first portions of saidblade closer to said certain pre-selected parts of said article than thespacing of said blade from said other parts of said article.
 22. Themethod of claim 21 wherein: said spacing of said blade first portions isabout one-third of the spacing of said blade from said other parts ofsaid article.
 23. The method of claim 20 wherein said article has anirregular shape with angled intersections of adjacent surfaces:presenting corner or sharply curved intersections, said methodcomprising: staging the sequence of shrinkage for said pre-selectedparts at said intersections.
 24. The method of claim 20 comprising:heating of aid heat sealing blade by an electrically activated flexiblecable heater provided within said blade.
 25. The method of claim 20comprising: staging the sequence of shrinkage of different parts of saidfilm about said article to produce a tighter fit of said film about saidpreselected parts than the fit of said film about said other parts ofsaid article. 26-55. (canceled)